• Korean Journal of Mathematics
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• 제29권3호
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• pp.473-481
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• 2021

In this paper, we investigate the relations between the growth of meromorphic coefficients and that of meromorphic solutions of complex linear differential-difference equations with meromorphic coefficients of finite logarithmic order. Our results can be viewed as the generalization for both the cases of complex linear differential equations and complex linear difference equations.

• Korean Journal of Mathematics
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• 제29권2호
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• pp.239-252
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• 2021

The prime target of this paper is to compare some relative (k, n) Nevanlinna defects with relative (k, n) Valiron defects from the view point of integrated moduli of logarithmic derivative of entire and meromorphic functions where k and n are any two non-negative integers.

• 대한수학회지
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• 제58권2호
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• pp.501-523
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• 2021

We study the geometry of the moduli space of elliptic stable maps to projective space. The main component of the moduli space of elliptic stable maps is singular. There are two different ways to desingularize this space. One is Vakil-Zinger's desingularization and the other is via the moduli space of logarithmic stable maps. Our main result is a proof of the direct geometric relationship between these two spaces. For degree less than or equal to 3, we prove that the moduli space of logarithmic stable maps can be obtained by blowing up Vakil-Zinger's desingularization.

• 대한수학회보
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• 제59권6호
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• pp.1495-1510
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• 2022

This paper aims to investigate the initial boundary value problem of the nonlinear viscoelastic Petrovsky type equation with nonlinear damping and logarithmic source term. We derive the blow-up results by the combination of the perturbation energy method, concavity method, and differential-integral inequality technique.

• 대한전자공학회논문지
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• 제12권1호
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• pp.12-17
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• 1975

광대역의 계수율을 선택 스윗치 없이 계측하기 위한 대수계수율회로에 관한 해석을 하였고 그에 의한 다데케이드 계수율회로의 구성방법과 실험결과를 지시하였다. 이 대수계수율회로는 주기적인 입력 펄스 뿐만 아니라, Poisson분포를 갖는 random한 펄스에 대하여도 대수적인 응답특성을 가지며 계수율 1pps로 부터 $10^5$pps까지 데케이드의 영역에 걸쳐 좋은 대수특성을 가지며 또한 낮은 영역과 높은 영역에서의 특성저하의 원인을 규명하여 양단에서의 특성을 효과적으로 보상하였다.

• 한국수학사학회지
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• 제27권6호
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• pp.409-419
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• 2014

In school mathematics, the logarithmic function is defined as the inverse function of an exponential function. And the natural logarithm is defined by the integral of the fractional function 1/x. But historically, Napier had already used the concept of logarithm in 1614 before the use of exponential function or integral. The calculation of the logarithm was a hard work. So mathematicians with arithmetic ability made the tables of values of logarithms and people used the tables for the estimation of data. In this paper, we first take a look at the mathematicians and mathematical principles related to the appearance and the developments of the logarithmic tables. And then we deal with the confusions between mathematicians, raised by the estimation data which were known as proportional parts or mean differences in common logarithmic tables.

• 대한수학회보
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• 제56권1호
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• pp.265-276
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• 2019

For a simple implementation, a linear convex splitting scheme was coupled with the Fourier spectral method for the Cahn-Hilliard equation with a logarithmic free energy. However, an inappropriate value of the splitting parameter of the linear scheme may lead to incorrect morphologies in the phase separation process. In order to overcome this problem, we present a nonlinear convex splitting Fourier spectral scheme for the Cahn-Hilliard equation with a logarithmic free energy, which is an appropriate extension of Eyre's idea of convex-concave decomposition of the energy functional. Using the nonlinear scheme, we derive a useful formula for the relation between the gradient energy coefficient and the thickness of the interfacial layer. And we present numerical simulations showing the different evolution of the solution using the linear and nonlinear schemes. The numerical results demonstrate that the nonlinear scheme is more accurate than the linear one.

• 대한한의진단학회지
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• 제9권2호
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• pp.72-82
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• 2005

Background and purpose: Bell‘s Palsy is a condition that causes the facial muscles to weaken or become paralyzed. It's caused by trauma to the 7th cranial nerve, and is not permanent. The aim of this study is to be convinced of differences between facial electrodermal activities of paralyzed side and those of normal side in acute stage of Bell's Palsy patients Methods: Electrodermal activity (EDA) was performed within 1 week after the onset of facial palsy and facial nerve electromyography (EMG) at 2 weeks after the onset. The recovery of facial nerve function was documented by House and Brackmann grading. All the patients were followed up weekly until recovery or up to 6 weeks. Results: There was significant differences (conductivity A: t=3.319, p=0.002; conductivity C: t=2.699, p=0.010) between facial electrodermal conductivities of paralyzed side and those of normal side in acute stage of Bell's Palsy patients (N=45). And the result showed that logarithmic scale of electrodermal conductivity A value ratio obviousely decreased with logarithmic scale of EMG zygomatic branch amplitude ratio (r=-0.472, p=0.143); logarithmic scale of capacitance B, logarithmic scale of EMG temporal branch amplitude ratio (r=-0.422, p=0.133); logarithmic scale of conductivity C, logarithmic scale of EMG buccal branch amplitude ratio (r=-0.545, p=0.083) (N=12). Conclusion: Electrodermal conductivities increased in paralyzed facial side in acute stage of Bell's Palsy patients.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1306-1310
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• 2009

The roughness coefficients were estimated by the Manning's equation for the measured stage and flow velocity of Bocheong stream basin in Kum river. The relationships between the estimated roughness coefficients and the geomorphologic factors were formulated by the linear, logarithmic, exponential and power type function, thereafter correlation equations were presented. The correlation analysis was performed between the measured stream length and the basin area of Bocheong stream basin by the linear, logarithmic, exponential and power type function, and correlation equation for the stream length was given. The roughness coefficient has strong correlationship with stream slope, but low correlation coefficients with stream length and basin area. For the correlationship with the roughness coefficients and the stream slope, the logarithmic type function has the smallest correlation coefficient, on the other hand, the exponential type function has the largest correlation coefficient. For the relationship between the stream length and the basin area, the correlation coefficient of the logarithmic type function shows the smallest value, linear type function shows the largest value.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권1호
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• pp.22-28
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• 2009

This paper presents a fast received signal strength indicator (RSSI) circuit for wireless communication application. The proposed circuit is developed using power detectors and an analog-to-digital converter to achieve a fast settling time. The power detector is consisted of a novel logarithmic variable gain amplifier (VGA), a peak detector, and a comparator in a closed loop. The VGA achieved a wide logarithmic gain range in a closed loop form for stable operation. For the peak detector, a fast settling time and small ripple are obtained using the orthogonal characteristics of quadrature signals. In $0.18-{\mu}m$ CMOS process, the RSSI value settles down in $20{\mu}s$ with power consumption of 20 mW, and the maximum ripple of the RSSI is 30 mV. The proposed RSSI circuit is fabricated with a personal handy-phone system transceiver. The active area is $0.8{\times}0.2\;mm^2$.